1. Field of the Invention
The present invention relates to a lighting apparatus utilizing LED chips.
2. Description of the Related Art
LED lighting apparatuses including LED chips have been developed as an alternative to a conventional lighting apparatus using e.g. a fluorescent lamp. A lighting apparatus to be attached to a ceiling is often called a ceiling light.
FIGS. 35 and 36 show an example of conventional LED lighting apparatus for use as a ceiling light (see JP-A-2008-300203, for example). The LED lighting apparatus 900 shown in the figure is used as attached to a ceiling 800. The LED lighting apparatus 900 includes a plurality of light source units 910, a reflective surface 920 and a cover 930. Each of the light source units 910 incorporates LED chips (not shown). The reflective surface 920 is a surface of a metal plate that is painted white. Light from the light source units 910 is reflected by the reflective surface 920 to travel downward, as shown in FIG. 35. The cover 930 covers the reflective surface 920 and is generally rectangular as viewed in plan. The cover 930 is made of e.g. a resin material that transmits light while diffusing, and hence, transmits the light, reflected by the reflective surface 920, downward in FIG. 35 while diffusing.
The edges of the cover 930 are rather distant from the reflective surface 920, so that light from the light source units 910 does not easily reach the edges. In particular, the amount of light reaching the four corners of the rectangle defined by the edges of the cover 930 is considerably small. Thus, when the LED lighting apparatus 900 is used, the four corners of the cover 930 may look dark.
Moreover, as shown in FIG. 35, the light source units 910 of the LED lighting apparatus 900 are arranged to emit light inward, in order that as much light from the light source units 910 as possible is reflected downward in the figure by the reflective surface 920.
According to the above-described arrangement, however, light from the light source units 910 does not easily reach the ceiling 800. Thus, the ceiling 800 to which the LED lighting apparatus 900 is attached may look dark when people in the room look up.